Hematuria is the abnormal presence of red blood cells in the urine (>3-4 RBC). Hematuria is divided in two categories:

• Microscopic Hematuria : Red blood cells in the urine are visible only with the microscope  in the general urinalysis.
• Macroscopic Hematuria (Gross Hematuria): There is such a large number of red blood cells in the urine that the urine is red-coloured. 

There are numerous causes associated with hematuria. Some of these are:

• Urinary tract infection (UTI) 
• Prostatitis (in men)
• Urolithiasis
• Heavy physical exercise
• Urinary tract Injury
• Pharmaceutical agents, such as anticoagulants (heparin, aspirin) or immunosuppressants (cyclophosphamide) 
• Cancer of kidneys, bladder, prostate